JPH05303027A - Optical fiber array and its substrate - Google Patents

Abstract

PURPOSE:To provide the optical fiber array and its substrate which dispense with grinding at the time of assembly, and also, can align a polarization plane of a polarization plane maintaining fiber with high accuracy. CONSTITUTION:On the upper plane part of a substrate 22, V-grooves 30 are provided in parallel to each other by separating them by a prescribed interval each, respectively. A recessed part for inserting a covered part 42 made of a resin of a polarization plane maintaining fiber 41 is provided so as to communicate with an end part of the V-groove 30. A groove 50 which intersects the V-groove 30 and extends from one side face of the substrate 22 to a side face of the opposite side. The polarization plane maintaining fiber 41 is provided in the V-groove 30. A resin compound adhesive agent 60 is applied so as to cover the rear part of the groove 50. A holding member 24 is provided in the upper part of the polarization plane maintaining fiber 41. By the resin compound adhesive agent 60, the polarization plane maintaining fiber 41, the substrate 22 and the holding member 24 are fixed integrally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber array and its substrate, and more particularly to an optical fiber array and its substrate for aligning and fixing a plurality of optical fibers.

[0002]

2. Description of the Related Art In optical fiber communication systems,
An optical fiber array is used in which a plurality of optical fibers are aligned and fixed at predetermined intervals. This optical fiber array usually includes a substrate 22 and a pressing member 24 as shown in FIG. Further, as shown in FIG. 7, a plurality of V-shaped grooves 30 are formed on the upper flat surface portion 22b of the substrate 22 at predetermined intervals. Then, V of the substrate 22
After the optical fiber 40 is arranged in the groove 30, the pressing member 2
4 is in contact with the outer peripheral end of the optical fiber 40,
The substrate 22, the optical fiber 40, and the pressing member 24 are integrally fixed via a resin adhesive 60 or the like.

[0003]

In the above-mentioned optical fiber array, in order to connect with the optical waveguide or the like, the tip end surface of the optical fiber 40, the side flat surface portion 22a of the substrate 22, and the side flat surface of the pressing member 24 are formed. The part 24a is arranged in the same plane. Therefore, when these are bonded by the resin-based adhesive 60, the resin-based adhesive 60 protrudes from the side plane portions 22a and 24a of the substrate 22 and the pressing member 24, and the resin-based adhesive 60 also adheres to the tip end surface 40a of the optical fiber 40. Agent 6
There was a problem that 0 was attached.

When the resin-based adhesive 60 adheres to the tip end surface 40a of the optical fiber 40, almost no light is transmitted. Therefore, a polishing process is required to remove the adhered resin-based adhesive 60.

Further, when the polarization-maintaining fiber 41 is used as the optical fiber 40, if the resin-based adhesive 60 is attached to the tip surface 41a, it becomes difficult to match the polarization plane. As shown in FIG. 8, the polarization-maintaining fiber 41 includes a stress applying portion 46 provided on both sides of the core 44,
A plane of polarization is formed in a predetermined direction via 46. Therefore, when using the polarization-maintaining fiber 41, the polarization-maintaining fiber 4 must be aligned unless the polarization plane is aligned in a certain direction.
When the optical fiber array is combined with another element, the polarization angle of the emitted light from the optical element 1 is incident on the element. For this reason, when an optical fiber array is manufactured by using the polarization-maintaining fiber 41 as the optical fiber 40, it is necessary to rotate the polarization-maintaining fiber 41 in the V groove 30 to adjust the polarization plane to a predetermined angle. There is. For this adjustment, while observing the front end surface 41a of the polarization-maintaining fiber 41 with a CCD camera, adjust the direction of the stress applying portion 46 to a predetermined angle, or arrange the polarizer and the photodetector in front of and behind the fiber array. The optical system is assembled by, and the light is actually incident, and the polarization plane is adjusted to a predetermined angle while measuring the polarization direction of the light emitted from the fiber array end surface 41a. In any of the adjusting methods, if the resin-based adhesive 60 is attached to the tip surface 41a of the polarization-maintaining fiber 41, it becomes difficult to observe with a CCD camera, and the polarization degree of the light emitted from the fiber array is also reduced. However, it is difficult to match the plane of polarization because the adhesive that adheres significantly deteriorates. Therefore, even if the resin-based adhesive 60 is removed by polishing thereafter, the polarization planes do not match, so that the polarization-maintaining fiber array can no longer be used.

Therefore, the present inventors, as shown in FIG. 9, attach the front end face 41a of the polarization maintaining fiber 41 to the substrate 22.
Also, a method has been devised in which the pressing member 24 is arranged so as to project from the side flat surfaces 22a, 24a by about 0.5 to 1 mm. According to this method, after the resin-based adhesive 60 is applied with the polarization-maintaining fiber 41 placed on the substrate 22, and when the pressing member 24 is mounted, the resin-based adhesive 60 protrudes from the side flat surfaces 22a, 24a. Resin adhesive 60
However, it is possible to prevent the polarization plane preserving fiber 41 from adhering to the tip surface 41a of the polarization plane preserving fiber 41. Therefore, the polarization plane of the polarization plane preserving fiber 41 can be aligned in a predetermined direction.

However, even with this method, since the tip portion of the polarization-maintaining fiber 41 and the resin-based adhesive 60 are protruded from the side plane portions 22a and 24a, the tip surface 41a and the side plane portion of the polarization-maintaining fiber 41. 22a, 24
A polishing step is also necessary to remove a resin adhesive 60 that has overflowed while making a in the same plane.

Furthermore, in the polarization-maintaining fiber 41, the stress imparting portion 46 rotates to some extent in the longitudinal direction inside the fiber. When this rotation is large, per 1 mm,
It can be 2-3 degrees. The rotation of the stress applying section 46 is random in the longitudinal direction of the polarization-maintaining fiber 41.
Therefore, even if the polarization plane of the polarization-maintaining fiber 41 is aligned with the protruding front end surface 41a, the polarization plane is displaced from a predetermined direction by the subsequent polishing, and as a result, the light emitted from the polarization-maintaining fiber 41 is emitted. However, there is a problem that the polarization angle is shifted, and when this optical fiber array is combined with another element, the light whose polarization angle is shifted enters the element.

Accordingly, it is an object of the present invention to provide an optical fiber array and its substrate that do not require polishing during assembly.

Another object of the present invention is to provide an optical fiber array and a substrate for the same, which can precisely match the polarization planes of the polarization-maintaining fiber.

[0011]

According to the present invention, an optical fiber is aligned and housed in each of a plurality of V grooves formed in a substrate, and the optical fiber is held by a pressing member. In the optical fiber array in which the substrate and the pressing member are integrally fixed by an adhesive, a groove crossing the plurality of V grooves is further provided, and an optical fiber array is obtained.

Further, according to the present invention, in a substrate of an optical fiber array, which has a V groove for accommodating a plurality of optical fibers in a line and is integrally fixed to the optical fibers together with a pressing member by an adhesive, A substrate for an optical fiber array is obtained, which is further provided with a groove crossing the plurality of V grooves.

A polarization-maintaining fiber can be used as the optical fiber.

Further, it is preferable that the groove extends from one side surface of the substrate to the opposite side surface.

[0015]

In the present invention, since the groove crossing the plurality of V grooves is provided, the adhesive flows out into the groove. Therefore, it is possible to prevent the adhesive from sticking out from the side flat surfaces of the substrate and the pressing member and adhering to the tip end surface of the optical fiber. As a result, no polishing is required to remove the adhesive after assembly of the fiber array.

Furthermore, since the adhesive can be prevented from adhering to the tip end surface of the optical fiber by the groove crossing the plurality of V grooves in this way, even when a polarization maintaining fiber is used as the optical fiber. It is not necessary to provide the tip end surface of the polarization-maintaining fiber beyond the side flat surface of the substrate and the pressing member. As a result, there is no need to polish the tip of the polarization-maintaining fiber thereafter, so that it is possible to prevent the polarization plane from deviating from a predetermined direction due to the polishing of the polarization-maintaining fiber. Therefore, the polarization plane can be adjusted accurately and easily.

Further, the groove crossing the plurality of V grooves is provided so as to extend from one side surface of the substrate to the side surface on the opposite side, so that the adhesive is more surely protruded from the side flat surface portion of the substrate and the pressing member. It can be prevented from adhering to the tip surface of the optical fiber.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 4 are perspective views for explaining one embodiment of the present invention.

As shown in FIG. 1, the upper flat surface portion 2 of the substrate 22.
In 2b, four Vs are provided at regular intervals.
The grooves 30 are provided parallel to each other. A recess 32 is formed in communication with the end of the V groove 30 for inserting a resin coating portion 42 of a polarization-maintaining fiber 41 described later. Further, a groove 50 that extends from one side surface of the substrate 22 to the opposite side surface across the V groove 30 is provided.

Next, as shown in FIG. 2, after removing the resin coating portion 42 covering the polarization-maintaining fiber 41 for a predetermined length, the polarization-maintaining fiber 41 exposed to the outside is covered with the V groove 30. Place inside. At this time, the front end surface 41a of the polarization-maintaining fiber 41 is placed in the same plane as the side flat surface portion 22a of the substrate 22 so that the polarization-maintaining fiber 4 can be formed.
1 is provided. The resin-coated portion 42 of the polarization-maintaining fiber 41 is arranged in the recess 32 of the substrate 22.

Next, as shown in FIG. 3, a resin adhesive 6
0 is applied so as to cover a portion of the substrate 22 that is behind the groove 50, a portion of the polarization-maintaining fiber 30 that is behind the groove 50, and the resin-coated portion 42 in the recess 32. Since the resin adhesive 60 flows into the groove 50, it does not flow out in front of the groove 50. In order to prevent the adhesive 60 from protruding in front of the groove 50 and to secure a sufficient adhesive force, it is necessary that the resin adhesive 60 sufficiently flows into the groove 50. For that purpose, the depth d of the groove 50 is preferably 0.6 mm or more, and the width w of the groove 50 is also preferably 0.6 mm or more. In this example, the depth d was 1 mm and the width w was 0.7 mm.

After applying the resin adhesive 60,
The angle of the polarization plane of the polarization maintaining fiber 41 was roughly adjusted.
Further, as the resin adhesive 60, Epotek 353N
D was used.

Next, as shown in FIG. 4, the pressing member 24
Are arranged above the polarization maintaining fiber 41. At this time, the side flat surface portion 24 a of the pressing member 24, the side flat surface portion 22 a of the substrate 22, and the tip end surface 4 of the polarization maintaining fiber 41.
The pressing member 24 is arranged so as to be in the same plane as 1a.

While slightly pressing the pressing member 24 from above, the polarization plane of the polarization-maintaining fiber 41 is aligned in a predetermined direction. This polarization plane adjustment is performed by the polarization-maintaining fiber 41.
The optical system is assembled by adjusting the direction of the stress applying portion 46 to a predetermined angle while observing the front end surface 41a of the optical disc with a CCD camera, or by arranging a polarizer and a photodetector in front of and behind the optical fiber array. It can be performed by either injecting light and adjusting the polarization plane to a predetermined angle while measuring the polarization direction of the emitted light. In this case, in this embodiment, since the groove 50 is provided, the resin-based adhesive 60 protrudes from the side plane portions 22a and 24a of the substrate 22 and the pressing member 24, and the tip surface 41a of the polarization-maintaining fiber 41 is formed. Can be prevented, and therefore, the polarization plane can be easily adjusted by any of the above adjusting methods.

Thereafter, the polarization maintaining fiber 41, the substrate 22 and the pressing member 24 are fixed to each other by the resin adhesive 60 while pressing the pressing member 24 more strongly from above to manufacture the optical fiber array 20. Also in this case, since the groove 50 is provided, the resin adhesive 60 is
Side plane portions 22a, 24 of the substrate 22 and the pressing member 24
The tip end surface 41 of the polarization-maintaining fiber 41 protrudes from a.
It can be prevented from adhering to a. Therefore, it is not necessary to perform polishing for removing the resin adhesive 60 even after assembly.

Furthermore, since the resin adhesive 60 can be prevented from adhering to the tip surface 41a of the polarization-maintaining fiber 41 by the groove 50 that crosses the plurality of V-grooves 30 in this way, the tip of the polarization-maintaining fiber 41 is prevented. The surface 41a is the substrate 22
Also, it is not necessary to provide the pressing member 24 by protruding from the side flat surfaces 22a and 24a. As a result, since it is not necessary to polish the tip of the polarization-maintaining fiber 41 thereafter, it is possible to prevent the polarization plane from deviating from a predetermined direction due to the polishing of the polarization-maintaining fiber 41.

The polarization-maintaining fiber 41 has a V groove 30.
It is supported by three points of the side surfaces 30a and 30b of the above and the lower flat surface 24b of the pressing member 24.

Further, in this embodiment, as shown in FIG. 3, the polarization plane of the polarization-maintaining fiber 41 was roughly adjusted before disposing the pressing member 24. However, such a rough adjustment is not performed. The polarization plane may be adjusted only after the pressing member 24 is provided.

Further, in this embodiment, the front end surface 41a of the polarization maintaining fiber 41 and the side flat surface portion 22 of the substrate 22 are used.
Since a and the side flat surface portion 24a of the pressing member 24 are in the same plane and the resin adhesive 60 does not adhere to the tip end surface 41a of the polarization-maintaining fiber 41, no polishing step is required. However, the polarization maintaining fiber 41
In order to adjust the front end surface 41a of the substrate 22, the side flat surface portion 22a of the substrate 22 and the side flat surface portion 24a of the pressing member 24 to be in the same plane, usually, the protrusion amount of the front end surface 41a of the polarization maintaining fiber 41 is visually observed. Is made to be zero, so that a slight protrusion and retraction of the tip surface 41a of the polarization-maintaining fiber 41 remains. Therefore, when more precise control of the protrusion amount of the tip surface 41a is required, the end surface can be polished.

In this embodiment, the deviation of the plane of polarization from the predetermined direction could be suppressed within ± 1 °. On the other hand, in the method shown in FIG. 9 in which the tip end surface 41a of the polarization-maintaining fiber 41 is projected and then polished, a polarization plane shift of about ± 5 ° occurs before and after polishing, and as a result, a predetermined direction is lost. The deviation from was as large as about ± 5 °.

FIG. 5 is a perspective view for explaining another embodiment of the present invention. An adhesive injection port 38 is provided on the pressing member 24.
Is different from the above-described embodiment. In the present embodiment, the polarization-maintaining fiber 41 is arranged in the V groove 30 of the substrate 22, and the pressing member 24 is then arranged on the polarization-maintaining fiber 41. The polarization preserving fiber 41, the substrate 22, and the pressing member 24 are fixed by filling the adhesive 60. Also in this embodiment, since the groove 50 is provided, the resin-based adhesive 60 is applied to the substrate 22 and the pressing member 24.
It is possible to prevent the light from protruding from the side flat portions 22a and 24a and adhering to the tip surface 41a of the polarization-maintaining fiber 41. Therefore, not only can the polarization plane be easily adjusted during assembly, but also after assembly, the resin adhesive 6
It is not necessary to carry out polishing to remove 0.

Although an optical fiber array using the polarization-maintaining fiber 41 has been described in each of the above embodiments, the present invention is applicable to an optical fiber array using the normal optical fiber 40 without the stress imparting portion 46. Can also be applied. Even in this case, the groove 50 allows the resin-based adhesive 60 to cover the substrate 22 and the side flat surface portion 22 of the pressing member 24.
a, 24a, and the tip surface 40 of the optical fiber 40
It can be prevented from adhering to a. Therefore, it is not necessary to carry out polishing for removing the resin adhesive 60 after assembly.

Further, the cross-sectional shape of the groove 50 is not limited to the shape of the above-mentioned embodiment, but may be, for example, a V-shaped cross-sectional shape.

[0035]

According to the present invention, since the groove crossing the plurality of V grooves is provided, the adhesive flows out into the groove. Therefore, it is possible to prevent the adhesive from sticking out from the side flat surfaces of the substrate and the pressing member and adhering to the tip end surface of the optical fiber. As a result, it is not necessary to perform polishing to remove the adhesive after assembling the optical fiber array.

Further, since the groove crossing the plurality of V grooves can prevent the adhesive from adhering to the tip surface of the optical fiber, even when a polarization-maintaining fiber is used as the optical fiber. It is not necessary to provide the tip end surface of the polarization-maintaining fiber beyond the side flat surface of the substrate and the pressing member. As a result, there is no need to polish the tip of the polarization-maintaining fiber thereafter, so that it is possible to prevent the polarization plane from deviating from a predetermined direction due to the polishing of the polarization-maintaining fiber. Therefore, the polarization plane can be adjusted accurately and easily.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining an embodiment of the present invention.

FIG. 2 is a perspective view for explaining an embodiment of the present invention.

FIG. 3 is a perspective view for explaining an embodiment of the present invention.

FIG. 4 is a perspective view for explaining an embodiment of the present invention.

FIG. 5 is a perspective view for explaining another embodiment of the present invention.

FIG. 6 is a perspective view for explaining a conventional optical fiber array.

FIG. 7 is a perspective view for explaining a conventional optical fiber array.

FIG. 8 is a cross-sectional view for explaining a polarization-maintaining fiber.

FIG. 9 is a perspective view for explaining an optical fiber array devised by the present inventors.

[Explanation of symbols]

 20 ... Optical fiber array 22 ... Substrate 24 ... Pressing member 30 ... V groove 40 ... Optical fiber 41 ... Polarization preserving fiber 50 ... Groove 60 ... Resin adhesive

Claims (6)

[Claims] 1. An optical fiber is aligned and housed in each of a plurality of V-shaped grooves formed on a substrate, and the optical fiber is bonded to the substrate and the pressing member in a state where the optical fiber is held by a pressing member. An optical fiber array integrally fixed by an agent, further comprising a groove crossing the plurality of V grooves. 2. The optical fiber array according to claim 1, wherein the optical fiber is a polarization-maintaining fiber. 3. The optical fiber array according to claim 1, wherein the groove is provided so as to extend from one side surface of the substrate to the opposite side surface. 4. A substrate of an optical fiber array having a V groove for accommodating a plurality of optical fibers in an aligned manner and integrally fixed to the optical fibers together with a pressing member by an adhesive, wherein the plurality of V grooves are provided. A substrate for an optical fiber array, which is further provided with a transverse groove. 5. The substrate of an optical fiber array according to claim 4, wherein the optical fiber is a polarization-maintaining fiber. 6. The substrate of the optical fiber array according to claim 4, wherein the groove extends from one side surface of the substrate to the opposite side surface.